What Do Caterpillar Eggs Look Like? A Quick Visual Guide

Caterpillar eggs are tiny and often overlooked, but they can be quite fascinating. They come in a variety of shapes, sizes, and colors depending on the species of butterfly or moth they belong to. Some eggs may appear round and smooth, while others could be oval and textured. Paying attention to these unique details can help you identify which caterpillar species will emerge from the eggs.

As you explore nature, you might notice caterpillar eggs laid on leaves, stems, or other suitable surfaces. They are usually found on or near the host plants that caterpillars feed on after hatching. The eggs may be laid individually or in clusters, depending on the butterfly or moth species. For example, the redhumped caterpillar lays its eggs in groups on host foliage.

Being able to recognize caterpillar eggs and their distinctive characteristics can be a valuable skill for gardeners, nature enthusiasts, or anyone interested in the life cycle of butterflies and moths. It can also help protect your plants from potential damage caused by caterpillars, as you’ll be able to spot their eggs before they hatch and take any necessary preventative measures.

General Appearance of Caterpillar Eggs

Color Spectrum

Caterpillar eggs come in a variety of colors, depending on the species. Common colors include shades of:

  • Red
  • Yellow
  • White
  • Green
  • Off-white

It’s important to note that colors can change as the eggs mature, which may make them more difficult to identify.

Size and Shape

Caterpillar eggs are usually small and round, although their size and shape can differ between species. Here are some examples:

  • Eggs of some species may be as small as a pinhead.
  • Others might be slightly larger, around the size of a sesame seed.

Texture

Caterpillar eggs can have different textures, too. For instance:

  • Some eggs might have a smooth surface.
  • Others may appear granular or rough.

Inspecting the eggs closely can help you determine their texture.

Seasonal Variation

The appearance of caterpillar eggs can vary by season. Generally:

  • Some species lay their eggs in early spring, as the weather starts to warm up.
  • Others may wait until summer or even fall, depending on their specific lifecycle and environmental requirements.

Keeping an eye on seasonal changes can help you spot and identify caterpillar eggs more easily.

Specific Species of Caterpillar Eggs

Monarch Butterfly Eggs

Monarch butterfly eggs are tiny, oval-shaped, and have a cream color. They are usually laid singly on a milkweed plant leaf, which serves as their food source. A noticeable characteristic includes raised ridges running vertically up their surface.

Example features:

  • Tiny (1mm in size)
  • Oval shape
  • Cream color
  • Single eggs on milkweed leaves

Black Swallowtail Butterfly Eggs

Black swallowtail butterfly eggs are light-green and spherical, found singly or in small groups on a variety of host plants such as parsley, dill, and carrot tops. They appear smooth and shiny, typically measuring around 1mm in diameter.

Example features:

  • Spherical shape
  • Light-green color
  • Single eggs or groups
  • Host plants: parsley, dill, and carrot tops

Pipevine Swallowtail Butterfly Eggs

Pipevine swallowtail butterfly eggs are small, reddish-brown, and spherical. They are often laid in clusters on the undersides of pipevine plant leaves, which serve as their only food source.

Example features:

  • Spherical shape
  • Reddish-brown color
  • Clustered on pipevine leaves

Zebra Longwing Butterfly Eggs

Zebra longwing butterfly eggs are small, light-yellow, and barrel-shaped. They are laid individually on passionflower vine leaves, with several eggs spread across the plant to ensure survival.

Example features:

  • Barrel-shaped
  • Light-yellow color
  • Individually laid on passionflower vines

Brimstone Butterfly Eggs

Brimstone butterfly eggs are tiny, about 1mm in size, and resemble a greenish-yellow, truncated cone. They are laid singly on the leaves of buckthorn or alder buckthorn plants, which act as their primary food source.

Example features:

  • Greenish-yellow color
  • Tiny, cone-shaped (1mm in size)
  • Single eggs on buckthorn plants

Gulf Fritillary Butterfly Eggs

Gulf fritillary butterfly eggs are pale-yellow and elongated, with several small ridges at the top. They are laid singly on the leaves of passionflower vine, which serves as their food source.

Example features:

  • Pale-yellow color
  • Elongated with ridges
  • Single eggs on passionflower vines

Eastern Black Swallowtail Butterfly Eggs

Eastern black swallowtail butterfly eggs are cream-colored and spherical, measuring approximately 1mm in diameter. They are laid singly on an array of host plants, including dill, parsley, and fennel.

Example features:

  • Cream color
  • Spherical shape (1mm in diameter)
  • Single eggs on dill, parsley, and fennel plants

Life Cycle of a Butterfly

Laying of Eggs

During the first stage of the butterfly life cycle, a female butterfly will oviposit, or lay tiny, cream-colored eggs, usually on the underside of a leaf. For example, monarch butterflies lay their eggs on milkweed plants. The choice of plant is crucial, as it serves as a food source for the hatching caterpillars.

Hatching of Larva

In about 4 days, the eggs hatch into worm-like larvae, also known as caterpillars. Upon hatching, the caterpillar’s main goal is to eat and grow. During this stage, they will molt multiple times, allowing them to increase in size.

Metamorphosis Into Pupa

When the caterpillar has reached its maximum size, it enters the pupa stage. The caterpillar forms a protective shell, called a chrysalis, around itself. Inside the chrysalis, the larva undergoes a transformation, or metamorphosis, into an adult butterfly.

Adult Butterfly Stage

After several days to a few weeks, the fully-formed adult butterfly emerges from the chrysalis. The adult butterfly has a new set of wings and is ready to reproduce, starting the life cycle all over again.

During each stage of the life cycle, butterflies undergo various transformations:

  • Egg: A tiny, cream-colored, and usually oval-shaped structure
  • Larva: A caterpillar, which feeds on its host plant
  • Pupa: A chrysalis, in which the caterpillar metamorphoses into a butterfly
  • Adult: A fully-formed, winged, and reproductive insect

By understanding the life cycle of a butterfly, you can appreciate the remarkable process these creatures go through to become the colorful and graceful insects we know and love.

Habitation and Host Plants

Common Habitats

Caterpillars can thrive in a variety of habitats, but they are commonly found in gardens, meadows, and forests. In these areas, they seek out host plants that provide the nutrition they need for growth. Several host plants are commonly available in gardens and meadows, making them ideal habitats for caterpillars.

Host Plant Preferences

Caterpillars have specific host plant preferences, depending on their species and the plants available in their environment. Some of the most common host plants caterpillars consume include:

  • Milkweed plants: These plants are a popular choice for Monarch butterflies and caterpillars. The leaves provide essential nourishment, and Monarchs lay their eggs on milkweed plants.
  • Parsley, fennel, and dill: Caterpillars from different species enjoy feeding on these plants, which are commonly found in gardens and meadows. These plants not only attract caterpillars but also enrich your garden with their lovely scents and decorative foliage.
  • Carrot and hop: Some caterpillar species find their nourishment in the leaves of these plants, making them essential host plants in their habitats.

By understanding caterpillar habitats and host plant preferences, you can support these fascinating creatures in their lifecycle and witness the beauty they bring to your surroundings.

Importance and Impact of Caterpillar Eggs

Role in Ecosystem

Caterpillar eggs play a crucial role in the ecosystem as they serve as food for various predators, like birds and insects. Additionally, when caterpillars hatch from these eggs, they contribute to the ecosystem by feeding on plants and converting it into energy for their growth and development. This process also helps in maintaining the population of plant species like aspen, birch, oak, linden, and ash.

For example, monarch caterpillars specifically feed on milkweed plants and indirectly assist in controlling the growth of this plant. Caterpillars also provide benefits to the ecosystem by becoming a food source themselves for their predators upon reaching the larva stage.

Significance in Gardening

Caterpillars, such as the larvae of butterflies and moths, can have both positive and negative impacts on gardening. On one hand, they are essential to the lifecycle of some beautiful species of butterflies and moths. However, their voracious appetites can sometimes cause damage to plants and crops. For instance, redhumped caterpillars can feed on the leaves of host plants while in their larva stage.

When managing caterpillars in a garden, it is essential to strike a balance between supporting pollinators and preventing significant damage. In some cases, natural predators like birds and insects can help control caterpillar populations. However, if an infestation occurs, gardeners may need to consider using targeted organic pesticides to protect their plants.

Here are some pros and cons of caterpillars in gardening:

Pros:

  • Provide a food source for birds and insects.
  • Contribute to the lifecycle of beautiful butterfly and moth species.
  • Can help control certain plants’ growth by feeding on them.

Cons:

  • Can cause significant damage to plants and crops.
  • May require the use of targeted pesticides to control infestations.

By understanding the importance and impact of caterpillar eggs in the ecosystem and gardening, you can make informed choices about how to manage these fascinating creatures in your own yard or garden. Just remember to consider their role in supporting biodiversity and weigh the pros and cons before taking any action.

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Probably Moth Eggs on Cannabis

 

Subject: Neatly organized cluster…please help.
Location: Portland, Oregon
August 20, 2017 6:35 am
hello I am growing legal recreational cannabis in Portland Oregon and have been very careful to keep an eye on the plants for various caterpillar larvae and other pests, this morning I noticed something I’m fairly sure was not there yesterday and I could only find one example of this they are neatly clustered on the bottom of one leaf towards the top of the plant. Nice little perfectly round white eggs. Attached is a photo. I’m thinking Moth of some kind maybe? Biggest goal is to prevent these from investing my few plants. Any advice would b greatly appreciated. Thanks for your time.
Signature: Casey Koelbl

Probably Moth Eggs on Cannabis Leaflet

Dear Casey,
Eggs can be very difficult to correctly identify, but we do agree with you that these appear to be Moth Eggs, but an exact identification my be impossible.  You can try isolating these eggs until they hatch, and then try raising them on fresh leaves until they get large enough to more accurately identify.  According to I Love Growing Marijuana:  “Caterpillars love marijuana plants! Corn Borer and Hemp Borer are the two most destructive caterpillars.”  Two sites with advice we would question are Alchimia because it pictures a Spurge Hawkmoth Caterpillar,
Hyles euphorbiae, NOT on Cannabis (see BugGuide for verification) and  Royal Queen Seeds because it pictures a Black Swallowtail Caterpillar that feeds on plants in the carrot family, not on hemp.  Dinafem advises:  “Look out for butterflies: If you see any butterflies resting on your plants, try to chase them away because they could be laying eggs. If you have seen butterflies on your plants, you should start to be suspicious and check for caterpillars.”  That sounds like ridiculous advice to us as we know of no butterflies with caterpillars that feed on Cannabis.  We would recommend keeping a close eye on your plants.  We recently created a new tag on our site What’s on my Woody Plant? so that we can address insects and other creatures found on Cannabis, and we hope to build this tag into a usable resource for growers so that they can distinguish between beneficial and problematic creatures they find on their crop.
P.S.  If you decide to try to hatch these eggs, please send a followup image or two our way.

Thank u so much for responding, I seriously appreciate it! I’ll do just that and I am going to grab a friend, sit down and give them a very thorough examination top to bottom to make sure they aren’t trying to start a city. Again thanks a ton for the help. Have a great day!

Letter 2 – The Vapourer from the UK: Caterpillar and Female laying Eggs

 

This Caterpillar turned moth

Vapourer Caterpillar

This Caterpillar turned moth
Location:  Heanor, Derbyshire, UK
August 21, 2010 7:39 am
Hi there I found this caterpillar on some plants outside my front door on the 23rd of July. A few days later it had turned into a chrysalis on the door to the to the bin store, which is above the plants. Then on the 20th of August I had noticed it had hatched and started to lay eggs, it is still laying eggs as I type this, but hasn’t seemed to grown wings, I’ve looked around for images of the caterpillar and moth but can’t seem to find a match, so I’ve given up and decided to ask the profesionals, also should I move the nesting site to somewhere there is vegetation for them?
Thank you for your time.
Mr Darryll Elston

Vapourer Moth laying Eggs

Dear Mr Elston,
Your caterpillar looks very much like a North American species called the White Marked Tussock Moth which BugGuide classifies in the subfamily Lymantriinae, the Tussock Moths.  Armed with that information, we headed for the UK Moths website and scanned the thumbnails for that group.  The UK Moths website considers Lymantriidae to be a distinct family unlike the subfamily status on BugGuide.  Scanning the thumbnails in the UK Moth family Lymantriidae quickly revealed the Vapourer.  The UK Moths page for the Vapourer,
Orgyia antiqua, provides this information:  “An unusual species in many ways, the males fly during the day (although the example depicted was attracted to light at night).  The females are virtually wingless, an attribute normally associated with winter-emerging species, but the adults are out from July to September, sometimes October in the south.  The female lays her eggs on what remains of the pupal cocoon, which then overwinter. When hatched, the very hairy caterpillars feed on a range of deciduous trees and shrubs.  The species is fairly common, especially in suburban habitats, over much of Britain, but more so in the south.”  That information is well documented in your photographs.  Thanks for contributing this new species to our website.

Vapourer Moth laying Eggs

Letter 3 – What's That Clutch of Eggs???

 

Subject: Eggs on Fennel Leaf
Location: Atlanta, GA
July 8, 2012 5:17 pm
These egss were deposited a couple of days ago on a bronze fennel leaf. They are small, about the size of a pin head. Hoping you can help identify. Thanks!
Signature: Amy R

Unknown Eggs

Dear Amy,
Eggs can be very difficult to identify, and though this formation seems distinctive, it does not look familiar to us.  Our best guess is that perhaps they are either a moth or a type of True Bug.  We will continue to research this.

As an update, I’ve attached a picture of some of the hatchlings. Some kind of looper? The picture was taken, today, 07/11/2012.

Eggs on Fennel Hatch into Caterpillars

Thanks Amy,
It seems our first guess, Moth Eggs, was correct.  Also, judging by the way the caterpillars move, they are the hatchlings of a Geometrid Moth, often called Inchworms or Spanworms.  We will see if we can determine what species feeds on fennel.

Letter 4 – Woolly Bear Hatchlings, we believe

 

tiny cone pattern shape eggs with bugs
Location: plano, texas
April 3, 2012 6:42 pm
I have these small bunch of cone pattern what look like eggs on my house i can see some small bugs but to small to tell what they look like or what it is some on my fence can’t find any thing of what it is
Signature: dbarber

Woolly Bear Hatchlings

Dear dbarber,
These appear to be newly hatched Tiger Moth Caterpillars, commonly called Woolly Bears.  The female moth often lays her eggs on the side of a building or other structure.  We cannot say for certain if our identification is correct, but we have a strong suspicion we are right.  The images we have linked to are not of a Texas species, but eggs and hatchlings of many Tiger Moths look similar.

Thanks that look’s like what it is i have been seeing these on my house for years and never knew what it was I do see those moths around my house all the time there’s one on my screen door right now. Thanks for the information

Letter 5 – Long-Tailed Skipper laying eggs. Caterpillar too!!!

 

medium butterfly laying eggs on bean plant
September 25, 2009
I discovered this butterfly laying eggs on the two varieties of beans I have growing, a bush type and vine type. The bush type is planted next to a square of soy beans.
The insect is approximately 2 inches wide and their flight pattern is sporadic and jittery with a distinct blue color on her fuzzy bottom, with multi colored through primarily brown wings. I only got a good look while she was laying her eggs, perched on a bean leaf leaving behind a stack on pale yellow eggs (pin head size) on the underside of the leaf. I have found these stacks on the top, bottom, and sides of bush leaves.
Upon further investigation of the plants I discovered many catepillars or larvae nestled in leaf fold cocoons. These are also pictured they are yellow with dark (almost black) heads, two ‘big’ red eyes and tiny necks, tiny black feet closest to the head and yellow orange feet toward end, the larvae/catepillar is yellow in color and has an orange tinge at the rear.
I have included photos though I did not get a wing spread shot. In these you can see the eggs, larvae/catepillar, and butterfly resting on a bean leaf.
betty marie
Sarsota, Florida zone 9/10 for gardening

Long-Tailed Skipper laying Eggs
Long-Tailed Skipper laying Eggs

Hi betty marie,
We applaud your powers of observation.  You have photographed a Long-Tailed Skipper, Urbanus proteus.  We are thrilled to have the photos of the egg laying process as well as the caterpillars.  As your letter supports, the food for the caterpillar includes plants in the pea family.  BugGuide has some wonderful images of this lovely species.

Long-Tailed Skipper Caterpillar
Long-Tailed Skipper Caterpillar

Letter 6 – Oakworm Eggs

 

Subject: anisota virgeniensis eggs
Location: winter park, fl
March 9, 2017 5:11 pm
I found a group of eggs outside on the floor which are from the Anisota virgeniensis family. what should I do with them? what do they feed on? how long do they take to hatch? I’m trying to figure out what tree to put them on, what leaves..
Signature: Natasha

Oakworm Eggs

Dear Natasha,
We are impressed that you were able to identify these eggs and puzzled why you did not know the answer to some of your questions once you had an identity.  Your eggs do indeed look like the eggs of a Pink-Striped Oakworm,
Anisota virginiensis, based on this BugGuide image.  According to BugGuide:  “Larvae feed on leaves of oak.”  We suspect the eggs will likely hatch when new growth is sprouting on the oaks.

I had put them on an oak tree, but I wanted to make sure I was doing the right thing because I would’ve been upset if I didn’t. I tend to overthink things and I like to be re-assured of an answer. Thank you for your response.

We are tagging your posting with the Bug Humanitarian Award.

Letter 7 – Oakworms and Eggs

 

Eggs? Galls? Magic space bubbles? A mystery!
Location: Toledo, OH
August 1, 2011 6:33 pm
Hey there! Oakworm (or so I think I remember) season is just starting around here, and most of the small oak trees at the park are ALREADY defoliated! Oy, it’ll be a bad year. Anyhow, I am curious if these are eggs coating the underside of the leaf or something else. It was very pretty, in a creepy sort of way.
Signature: Katy

Oakworms and Eggs

Hi Katy,
These Oakworms are the caterpillars of moths in the genus
Anisota (see BugGuide).  When they are really plentiful, Oakworms can defoliate trees.  It is our theory that the eggs, yes they are eggs, in the photos are also Oakworm eggs, but alas, when they hatch, they will not have anything to eat.  Thanks for sending us your great photographs.

Oakworms and Eggs

 

Authors

    by
  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

7 thoughts on “What Do Caterpillar Eggs Look Like? A Quick Visual Guide”

  1. I also found those tiny blue eggs on my dill weed. They hatched into tiny inch (millimetre) worms, too. JL Prince Rupert, BC Canada I posted an image of the eggs and worms on BugGuide.net ID request. No one has ID them yet, so thanks for this.

    Reply
  2. Found 14 greenish eggs on a vine that the long tail skipper likes. There were 6 on each straight line and another 6 in straight line. At the tip and bottom was one egg on tip and one on bottom. Wondering what it could be. The eggs after a wk. are turning clear transparent.

    Reply
  3. Hi,
    Just at the school I went there was a dead mother oakworm moth with many eggs on her. I tried to place these on the tree but most did not stick so I brought them back in a container. My question is: If the eggs fall near an oak tree will they do fine or do they need to be stuck on the oak leaf? I would think they would be ok but I am not sure. thank you

    Reply
  4. Hi,
    Just at the school I went there was a dead mother oakworm moth with many eggs on her. I tried to place these on the tree but most did not stick so I brought them back in a container. My question is: If the eggs fall near an oak tree will they do fine or do they need to be stuck on the oak leaf? I would think they would be ok but I am not sure. thank you

    Reply
  5. Today is August 14th 2021.
    We had put up very fine bird netting over our outdoor chicken coop and these eggs have been layed all over it I tried spraying it with the hose to remove them with no luck. I guess the lucky part will be when they hatch, our chickens and ducks will have a feeding frenzy.

    Reply

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